Type 1 · Individual ✓ Active NPI ✓ Valid NPI checksum
Dr. Guillermo Selim Simon, M.D.
Specialist in Potomac, MD · enumerated 2006.
Data current as of Jul 13, 2026 · sourced from CMS NPPES
National Provider Identifier
1598707523
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Registry record
Entity type Individual (Type 1)
Name Dr. Guillermo Selim Simon
Credential M.D.
Sex Male
Practice address 11044 Powder Horn Dr, Potomac, MD, 20854
Phone (301) 299-4171
Fax (301) 983-9185
Enumeration date Jun 12, 2006
Last updated in NPPES Jul 8, 2007
Taxonomy & licenses
MD · Doctor of Medicine: A physician who completed medical school (allopathic medicine), residency training, and state licensure.
About the MD credential
What is an NPI number?
A National Provider Identifier (NPI) is a unique 10-digit number that CMS assigns to every U.S. healthcare provider and organization under HIPAA. Type 1 NPIs identify individual providers; Type 2 NPIs identify organizations. The NPI appears on insurance claims, prescriptions, and credentialing paperwork, and never changes, even if the provider moves or changes specialty.
Frequently asked questions
Is NPI 1598707523 active?
Yes, as of the latest NPPES snapshot, NPI 1598707523 is active (record last updated 2007-07-08).
How do I verify Guillermo Simon's NPI record?
Cross-check NPI 1598707523 against the official CMS registry at npiregistry.cms.hhs.gov. This page mirrors the same public NPPES data with a monthly snapshot.
Source: CMS NPPES (public data). Snapshot 2026-07-13. Provider record last updated 2007-07-08.